Gas turbine engines and other types of turbo-machinery require routine field maintenance and/or repair. Such maintenance or repair may require the disassembly of certain components of the gas turbine engine. For example, turbine shroud blocks may need to be removed in order to obtain access to the turbine buckets. These turbine shroud blocks generally are positioned just outboard of the turbine buckets and may be held in position by a number of retaining pins. The retaining pins typically are installed radially through threads in a turbine casing and into a receiving hole in the shroud block. The retaining pins generally include a plug at one end thereof. The retaining pins may be difficult to remove during maintenance. Specifically, the application of too much torque may shear off the plug in the turbine casing.
When retaining pin plugs are sheared off during field maintenance, the plugs generally are drilled out by hand using numerous drill bits, grinding burs, and the like. This hand drilling, however, sometimes causes damage to the turbine casing threads or elsewhere. Moreover, access to the broken plugs on, for example, the lower half of the turbine casing may be difficult to reach and requires precision work in often cramped quarters.
There is therefore a desire for improved systems and methods for removing broken shroud retaining pins and the like from a turbine casing. Such systems and methods should provide for quick removal of the broken shroud retaining pins while preventing damage to the turbine casing.